Object detection apparatus

Abstract

During a first scanning duration in which projection light is reflected by a first reflection surface of a mirror of the rotary scanning unit, light emitting elements are caused to sequentially emit light, a light receiving element corresponding to a light emitting element in a light-emitted state is caused to sequentially receive the reflection light, and a light reception signal output from the light receiving element in the light-received state is sequentially selected by a signal selection unit. During a second scanning duration in which the projection light is reflected by a second reflection surface of the mirror, a specific light emitting element of the light emitting elements is caused to emit light with a prescribed period, the light receiving elements are caused to sequentially receive the reflection light, and the light reception signal output from the light receiving element in the light-received state is sequentially selected.

1 . An object detection apparatus comprising:
 a plurality of light emitting elements;   a rotary scanning unit that comprises a mirror, and by causing the mirror to rotate, reflects projection light projected from the light emitting elements by the mirror and scans the reflected projection light over a prescribed range;   a plurality of light receiving elements each of which receives reflection light of the projection light and reflected from an object in the prescribed range and which outputs a light reception signal in accordance with a light-received state;   a signal selection unit that selects any of light reception signals output from the plurality of light receiving elements; and   an object detection unit that detects the object based on the light reception signal which is selected by the signal selection unit,   wherein the mirror comprises a first reflection surface and a second reflection surface that do not belong in a same plane,   wherein during a first scanning duration in which the projection light is reflected by the rotary scanning unit from the first reflection surface and is scanned over the prescribed range, the plurality of light emitting elements are caused to sequentially emit light, the light receiving element that corresponds to a light emitting element in a light-emitted state of the plurality of light receiving elements is caused to sequentially receive the reflection light, and the signal selection unit is caused to sequentially select the light reception signal that is output from the light receiving element in the light-received state, and   wherein during a second scanning duration in which the projection light is reflected by the rotary scanning unit from the second reflection surface and is scanned over a prescribed range, a specific light emitting element of the plurality of light emitting elements is caused to emit light with a prescribed period, the plurality of light receiving elements are caused to sequentially receive the reflection light, and the signal selection unit is caused to sequentially select the light reception signal that is output from the light receiving element in the light-received state.   
     
     
         2 . The object detection apparatus according to  claim 1 ,
 wherein a width of the second reflection surface in parallel with a scanning plane for the projection light resulting from the rotary scanning unit is narrower than a width of the first reflection surface in parallel with the scanning plane.   
     
     
         3 . The object detection apparatus according to  claim 1 ,
 wherein the mirror is formed in a plate shape,   wherein the first reflection surface is provided on a plate-shaped surface of the mirror, and   wherein the second reflection surface is provided on a side surface of the mirror which has an area smaller than that of the plate-shaped surface.   
     
     
         4 . The object detection apparatus according to  claim 1 ,
 wherein the plurality of light emitting elements are arranged so as to be aligned in a direction perpendicular to the scanning plane for the projection light resulting from the rotary scanning unit, and   wherein during the first scanning duration, the light receiving element corresponding to the light emitting element in the light-emitted state and also corresponding to a reflection direction of the projection light resulting from the first reflection surface is caused to sequentially receive the reflection light.   
     
     
         5 . The object detection apparatus according to  claim 1 ,
 wherein during the first scanning duration, the object detection unit measures a distance to the object based on the light-emitted state of the light emitting element and based on the light reception signal that is selected by the signal selection unit, and   wherein during the second scanning duration, the object detection unit determines whether the object is present or absent, based on the light-emitted state of the light emitting element and based on the light reception signal that is selected by the signal selection unit.   
     
     
         6 . The object detection apparatus according to  claim 1 , further comprising:
 an analog-to-digital converter that converts the light reception signal in analog form, which is selected by the signal selection unit, into a light reception signal in digital form, and outputs the light reception signal to the object detection unit,   wherein the analog-to-digital converter is caused to intermittently operate so as to correspond to switching of selection of the reception light signals by the signal selection unit.